Hoisting and lowering devices for boards or plates



Jan. 7 1958 K. E. KLEVHOLM HOISTING AND LOWERING DEVICES FOR BOARDS OR PLATES Filed Jan. 25, 1957 INVENTOR. fi 0 1 76 1 4 01 N BY M United States Patent HOISTING AND LOWERING DEVICES FOR BOARDS OR PLATES Karl Eric Klevholm, J ohanneshov, Sweden Application January 23, 1957, Serial No. 635,761

Claims priority, application Sweden February 4, 1956 4 Claims. (Cl. 31139) This invention relates to a device for hoisting and lowering a board or plate in relation to a support therefor.

Different means have heretofore been suggested for adjustably supporting a board or plate, for example the board of a table, on a support, so as to permit the adjustment of the height of the board or the like. Such known means comprise for example a central, essentially vertical screw mounted on the underside of the board and screwed in a corresponding nut element in the support so as to permit adjustment by rotation of the whole board about the central axis of the screw, which renders this device unhandy and often gives unsatisfactory stability to the board. Means are also known for this purpose comprising one or more rods or tubes extending from the board downwards through corresponding tube elements of the support so as to be vertically slidable therein. The rods or tubes can be fixed at dififerent levels in relation to the support by pins inserted through holes both in the tubular elements of the support and in the rods. In devices of the last kind the adjustability of the height of the board is dependent of the spaces between the holes and the insertion of the securing pins in these holes is difiicult, as it must be effected successively for each rod separately.

It is a purpose this invention to liminate the disadvantages of previously known means of this kind and to provide means which permit a very easy and simultaneous adjustment of several supporting elements of a board or plate on a support, for example the four legs of a table for adjusting the height of the table.

This purpose is essentially attained by providing a support with the one element of at least two screw-and-nut connections, the other elements of which have their ends facing the board or plate provided with a crank, the crank pin of which is rotatably mounted in the underside of the board or plate.

An embodiment of the invention is by way of example diagrammatically illustrated in the accompanying drawing, in which Fig. 1 shows a table, specially designed for children in the growing age and provided with the adjusting means according to this invention. Fig. 2 is a vertical section at an enlarged scale through a leg element of the table.

The table illustrated comprises a support unit, itself comprising four vertical tubular leg elements 1 maintained at desired spaces and angles by horizontal stay bars or tubes 2. Each of the tubular leg elements is at a distance from both ends provided with a nut 3 fixedly mounted in the leg element for example by welding or by any other appropriate fastening means. At their upper ends the leg elements have inserted bushings 4. The legs of the table also comprise leg elements in the form of rods 5, having their lower, screw-threaded ends 6 screwed into the nuts 3 and a smooth intermediate portion 7 guided in the bushing 4 for both rotational and longitudinal motion. At their upper ends the rods have a ice crank arm 8, into the free end of which is inserted a crank pin 9 projecting vertically upwards and having an upwardly widened end portion fitted into a corresponding recess in a plate 10, fixed on the underside of the table board 11 by means of screws 12.

A stop screw 13 parallel with the rod 5 is screwed through the crank arm 8 to cooperate with a corresponding recess in the plate 10 to secure the crank arm against rotation around the crank pin 9 in the plate 10.

The device above described is assembled and operated in the following manner.

Before screwing the plates 10 onto the underside of the table board 11 by means of the screws 12, the rods are inserted through the bushings 4 and screwed down into the nuts 3 so that the uppermost face of the crank pin 9 of all four legs are in the same horizontal plane. The

crank arms 8 are simultaneously all four turned in the same direction, so that they are parallel. Thereafter the plates ii are mounted onto the underside of the board 11, their positions having been previously marked on the lower face of the table board 11, so that the spaces between the holes for the crank pins 9 are the same as the spacing of the leg elements 1 and 5. The height of the table is then adjusted by laying a hand on its upper surface and moved in a circle with the table board 11, so that all four cranks 3, 9 are synchronously rotated. When the table thereby is adjusted at the desired level, the locking screws 13 are screwed into the corresponding recesses ensuring that the table board takes the correct position in relation to the crank arms and that the plates Ill are pressed upwards with their recesses in tight engagement with the widened end portions of the crank pins 9. Thereby any undesired play and rattling noise of the joints is prevented. By making the bushings: l of plastic sound-absorbing antifrictional material, every rattling noise is prevented there even after a long time of use of the table.

It is to be observed that the invention is not limited to the embodiment described above and illustrated in the accompanying drawing. The means for hoisting and lowering can be used in any connection where it is desired to allow the adjustment of a board or plate with regard to a support therefor. It is not either necessary to have the screw elements of the support formed as tubular elements with the rods screwed therein, it being also possible within the scope of the protection claimed to have the support comprising vertical rods screwthreaded at their upper end portions and to have corresponding nuts mounted in downwardly extending, tubular leg portions provided with cranked upper ends to cooperate with the underside of the board or plate. The locking means may also be replaced by any appropriate, known construction for locking means. The crank pin can be replaced by a recess in the crank arm engaged by a pivot on the plate.

I claim:

1. Means for hoisting and lowering a board or plate in relation to a support therefor, in which the support comprises the one elements of at least two screw-andnut connections, the other elements of which have their ends facing the board or plate provided with a crank, the crank pin of which is rotatably mounted onto the underside of the board or plate.

2. Means for hoisting and lowering a board or plate in relation to a support therefor, in which the support comprises two or more parallel, essentially vertical tubes having nuts fixed at the inside thereof at a distance from both ends of the tubes, a corresponding number of rods, each having its lower, screw-threaded end portion screwed into each of said nuts, a crank at the upper end of each of said rods, said ends facing the board or plate and the crank pins of said cranks rotatably mounted onto the underside of the board or plate.

3. Means for hoisting and lowering a board or plate in relation to a support therefor, in which the support comprises two or more parallel, essentially vertical tubes having a nut fixed at the inside thereof at a distance from both ends of the tubes, a corresponding number of rods, each having its lower, screw-threaded end portion screwed into each of said tubes and nuts, a smooth middle portion of said rods being guided for rotational and longitudinal motion through a bushing of sound-absorbing and antifrictional material inserted into the upper end of each of saidtubes of the support, a crank at the upper end of each of said rods, said ends facing the board or plate and the crank pins of said cranks rotatably mounted onto the underside of the board or plate.

4. Means for hoisting and lowering a board or plate in relation to a support therefor, in which the support comprises the one elements of at least two screw-and-nut connections, the other elements of which have their ends facing the board or plate provided with a crank arm,

into which a :crank pin with a conically widened upper end is inserted through a bearing hole in a bearing plate to be fixed onto the underside of the board or plate, said bearing hole having an upper widened portion corresponding to the upper widened end of the crank pin, said crank arm supporting further a stop screw adapted for pressing the bearing plate away from the crank arm and thereby bringing the widened end of the crank pin into frictional engagement with the widened portion of the bearing hole in the bearing plate for securing the crank from rotation.

References Cited in the file of this patent UNITED STATES PATENTS 8,970 Marsh May 25, 1852 1,133,804 Kaufman March 30, 1915 1,927,598 Oschlichter Sept. 19, 1933 2,368,748 Doty Feb. 6, 1945 2,550,306 Scoper Apr. 24, 1951 2,582,791 Page Jan. 15, 1952 2,614,012 Yuan Oct. 14, 1952 

